Do Tesla Drivers charge up with with lowest cost electricity? TOU rates

[NealRoche]

Hi
I've been driving electric for two years. Maybe next year I can afford a Model S. I have a start up business developing tools for EV Charging (EVSE test equipment)

A question for the forum... I read that only 30% of EV drivers use 'Time of Use' electric rate plans in California. If the other 70% of drivers are paying regular residential rates for charging, they are paying way too much. They could be getting 30 -50% lower charging costs.

Why is this?
1. Don't know about EV rate plans
2. Don't really care about energy bill / solar panels keeps the bill low
3. It's too much hassle to get new/2nd meter installed to take advantage of EV rate plans
4 ??

Thanks
Neal

 

[rbergquist]

I have solar and EV rate with PG&E in Northern California. Solar coupled with EV rate is even better as you generate power & generate credits at a high price and consume it at low cost rate. This has stretched my effective solar generation capability. Nice thing is that no new meter is required. When I placed my order for the Tesla I upped my solar panel count to accommodate the projected usage. This combination keeps me in the lowest tier rates & minimized the capital cost for solar.

I use the Tesla timed charging and it works well for initiating charging. It would be nice if it had a stop time so it would stop charging when rates go up. Also needs to be a bit more flexible to match rate plans as weekdays & weekends have different times to charge/avoid.

If people aren't looking at the whole system picture, they're missing out on savings.

 

[Hometheatremaven]

With San Diego Gas & Electric, it isn't necessary to get a second meter; we have a Time-of-Use-2 (TOU2) plan which has three tiers of rates.
I think most of the members of our San Diego Tesla Club use this rate, or the regular TOU rate if they have a second meter.

 

[RandyS]

With San Diego Gas & Electric, it isn't necessary to get a second meter; we have a Time-of-Use-2 (TOU2) plan which has three tiers of rates.
I think most of the members of our San Diego Tesla Club use this rate, or the regular TOU rate if they have a second meter.

I work for the utility in San Diego, and we actively encourage drivers to take advantage of our EV rates...David, to be correct about it, I wouldn't say there are three "tiers", but rather, there are three different Time Of Use periods and each one has a difference price for energy. If you charge in the midnight to 5am "Super off-peak" time period, the charging will be cheapest. Or even in the "Off peak" time period, the price will be cheaper than the peak time of the day...You can even save more once you get on the EV-TOU2 rate by moving heavy loads out of the peak time period, such as pool pumps, etc. and re-program them to come on during the off-peak or super off-peak time periods...

Once you set the timer on the car, you're set to go....

 

[voidptr]

I think other towns around here in NC have better TOU tariffs, but my town is a wash unless you're never home during the day and smelting aluminum in the middle of the night.

With the non-TOU plan, it's $11/mo connection fee and 11c/kWh. With the TOU plan, it's $22/mo connection fee, 22c/kWh peak, and 5c/kWh off-peak.

I'd have to use ~200 kWh off-peak just to offset the extra connection charge, and then on-peak is double what it was before. It's just as likely the TOU would cost more than the standard plan, particularly during the summer when the AC is about 600 kWh peak. Without installing something like TED for a few months and doing the math, it's kind of a gamble.

 

[NealRoche]

Thanks for the comments.

The TOU rates I get from Southern Cal Edison with just one meter mean I need to be careful about what energy I use during peak times. I'd prefer if my EV was on its own meter.

 

[montgom626]

5 cents per kW TOU 7 pm to 7 am and 5 cents all day Saturday and Sunday. I always feed my MS the cheapest electricity I can get.

 

[earlyretirement]

I went with the 2nd dedicated SDGE TOU 2 EV rate. I posted a separate thread here about it

My experience getting a dedicated EV TOU 2 electric meter with SDGE in San Diego

I do think ultimately it will be worth it. Besides the summer months when we use AC, our usage is quite low even having a larger house. Plus we probably will get the Model X next year as well. We only plan to charge our EV's in the super off peak rates so this should be the best bang for the buck.

 

[jerry33]

Where I live it works out to be more expensive unless you drive a couple of hundred miles a day. Although nights are free, days are far higher on a TOU plan.

 

[ItsNotAboutTheMoney]

By EV, do you mean BEV or PEV. That can make a big difference to use.

As others point out TOU can sometimes carry such a significant additional meter cost that it's not worth it. It also deoends on relative pricing and pattern of home use. This problem could be fixed by having every meter be a smart meter capable of time of use and mandating TOU or real-time pricing. I think the net benefit would be significant as it would properly price the demand and reward peak-shaving and efficiency appropriately. When the pricing model is wrong, the market is wrong.

 

[MarkR]

We have and benefit from a TOU rate, but it would cost us money to use an EV rate because the EV rate doesn't coordinate well with our solar plan. We've tried to convince Arizona Public Service that this is silly, but to no avail.

 

[ZBB]

We have and benefit from a TOU rate, but it would cost us money to use an EV rate because the EV rate doesn't coordinate well with our solar plan. We've tried to convince Arizona Public Service that this is silly, but to no avail.

APS is less than forthcoming when it comes to their EV rate to begin with. When they called to discuss the potential savings (supposedly ~$300 per year) with using the EV plan, they refused to share any details in writing.

I eventually got them to run the EV plan with my prior 12 months actual usage (ie pre-Tesla) so I could compare the baseline with my prior bills -- turns out that increased my baseline cost by ~$20 per month. Tesla charging would save a bit on the EV rate, but my calc shows perhaps ~$10 per month if I only charged during the super off peak period. So I figured the EV plan would cost ~$120 per year MORE than our current rate plan -- so their estimate of $300 per year savings just didn't hold up. If they had shared the calculation in some way, it could have confirmed which estimate (theirs or mine) was more likely to be closer to reality...

Combined that with already being on a grandfathered TOU plan (9am-9pm peak, weekdays only), and that the EV rate is only available through 2014 (its a pilot program...), we decided to stay on the grandfathered plan.

So far, the charging costs have been pretty close to (actually slightly under) what I estimated prior to buying the Tesla...

 

[Tesla 940]

I believe the SCE Los Angeles is moving everyone to TOU starting in 2014. As for me - I've been on TOU for 10 years since I got my solar panels. When I got the Roadster, 3 years ago, I changed to TOU EV - not sure what the benefit was suppose to be. Never the less - no electric bill for 10 years now!

 

[Roxanne]

I live 40 miles north of San Francisco. I called Solar City to install the high power charger because they had the most experience. Then decided to go with them for my solar power. I've heard nothing but bad things about them from local solar power companies but they aren't true. They had by far the best plans available.

I chose the prepay electricity for 20 years at fixed price of 9 cents a kWh. They figure out the size of the system and install it with TOU. I get the credits at the highest rate and charge at the lowest rate. If the system produces more than they predicted, I get the extra credit. If the system should produce less, Solar City will pay me the difference.
With a high power charger it gets the job done during off peak hours so no need to have an end timer to avoid going into the more expensive time period. It currently only charges at 60 amps because they were having problems with fuses blowing above that but it can supposedly go to 80 amps. At 60 amps it charges at about 42 mph. I've never been close to empty but if I was, it wouldn't take more than 7 hours if I needed a full charge.

Solar City was fantastic. No other company bothered to do wind stress testing to determine how many stanchions were needed to hold the panels on my roof. But then no other company still owned the system on my roof and had a vested interest that it not blow away in the next 20 years. They even upgraded my panel to 200 amps for free. Total bill for high power charger installation and 20 years of power for my car was $5600. I do think I will be driving more than I used to so underestimated the kWh I would use. I didn't count road trips as I'd be using the super chargers, but I enjoy driving now so much more in my Model S.

 

[Lloyd]

All solar companies are required to do wind stress analysis to permit your installation. "There's no free lunch"